Rear Pads (simple):The rear pads are easy because you don’t have to remove the calipers.

1.Open the brake fluid reservoir under the hood.

2.With you hands on the weights, pull/squeeze the brake pads away from each other and away from the rotor to give yourself more room to work with.

3.Using either a very small screwdriver or a punch, hammer out the retaining pins from the outside of the caliper towards the inside. All you have to do is get them past the initial notch and they should pull right out.

Note that there is a retaining spring that pushes against these pins and against the pads. You may have to push the spring back with your finger in order to remove the pins completely. Once one pin is removed, you will be able to remove the spring (or it will fall out) and easily remove the other pin.

4.The pads will now pull right out of the caliper.

5.The right rear brake set has a pad wear sensor (the left rear does not) on the inside brake pad. To remove the sensor, just pull it straight out of the pad. No tools are necessary. The pads that I used (Carbotech AX6) did not have cut-outs for the sensor, so I just taped the sensor back over itself with electrical tape, and made sure it was behind the caliper and out of the way of the wheel.

6.Backing Plates: All of the stock pads on the 135 have very thin, metal shims/backing plates on them. I believe that these are used to hold the pad in place in the caliper. Both the Hawk and Carbotech aftermarket pads were modeled after the stock pads including these plates, therefore, the aftermarket pads are actually thicker than the stock pads. If you put the stock backing plates onto the aftermarket pads they will be too thick to fit into the calipers. EDIT: Hawk and other have since produced correctly sized pads which will accept the stock backing plates.

I mention this, because there is a consequence to not putting the backing plates on the aftermarket pads (see end of post).

7.Now you can put the replacement pads back into the caliper and reverse the steps you took to get the stock pads out. Push the pins through from the inside of the caliper to the outside (opposite direction from removal). Note that you will have to use that punch again to get the retaining pins fully back into their original position. Make sure that they make it all the way through the caliper and stick out as shown in the pictures.

Tools Required:1.) 10mm Hex key/driver (Must be very strong. Cheap tools will break)*If your hex tool is not very long, or you are using a normal sized ratchet you will need additional leverage. I used the top piece of my floor jack handle to extend the length of the tool.

2.) T-40 Torx bit/driver

Instructions

1. Open the brake fluid reservoir under the hood.

2. In order to make room to fit the new pads you must pull the pads away from the rotor. I actually pushed a flat-head screwdriver in between the pads and the rotor and leveraged them away from the rotor. You have to be careful not to damage your rotors. Make sure that you do not push the end of the screw driver into the rotor surface.

3. Using the T-40 Torx bit, loosen and remove each of the 4 retaining pins. Note that on the front caliper there is one pin per corner, whereas on the rear calipers there were only 2 pins that spanned the entire caliper. The yellow arrows are pointing towards the pins on the back side of the caliper. Also, the retaining spring on the front caliper does not need to come out, and it will just stay in place while you perform this service. EDIT: It is not absolutely necessary to remove all 4 retaining pins. I have since found that removal of one pin from each side of the caliper allows for easy access.

4. Now it’s time to get strong. Using your quality 10mm hex key/driver you must remove the caliper bolts which hold the calipers to the suspension knuckle. On my car these bolts were VERY firmly attached and were quite difficult to remove. I actually stopped at first and called my service tech to make sure the bolts weren’t reverse threaded. He said they were not, but he didn’t have the exact torque specs for the bolts. He told me that for caliper bolts the dealership uses the old German spec of “Gooduntight”.

The hydraulic brake lines are still attached to the brake caliper, so you will not be able to completely remove the caliper from the wheel well while working on it. Be sure to have a firm grip on the caliper when you remove the bolts (these 6-piston monsters are not super light). It was useful to have a second set of hands to help here. Once the caliper bolts are removed you can pull the caliper away from the rotor and swap the pads.

*As in the rear, there are backing plates which I did not use on my new pads. EDIT: See note above regarding newer pads. I now use the stock backing plates for stock pads and race pads alike.* The left front brake set has a wear sensor on the inside pad. As in the rear you can just pull this straight out of the pad. For the front I taped the sensor back over the hydraulic line to keep it out of the way. EDIT: Newer Hawk (and other) pads have a cut-out for the sensor, so feel free to reinsert the sensor into the new pads.

5. Once the new pads are in you can put the caliper back on the rotor and attach the caliper bolts. Attach the caliper bolts firmly (they are quite important) and then reinsert each of the four retaining pins until they are firmly in place. I will research the correct torque setting for these pins and the caliper bolts.

Notes:1. Although I did not use the shims that come on the stock pads, some people have actually shaved down their new pads in order to get the shims to fit. I am not sure what the long-term consequences of not having them will be, but I can tell you what the short-term effects are. When I was executing the bedding procedure for the new pads, each of the pads individually popped into place under my first significant braking run. They actually moved up in the caliper until they were firmly against the pins. This was scary at first because it's very audible when it happens. I can only assume that the backing shims would keep the pads in one place. I also had to do a 3-point turn after my bedding procedure and when braking in reverse at least one of the rear pads popped back the other direction. The pads couldn’t be moving more than 1-2mm but it’s something I’d like to look into further. EDIT: Using new Hawk pads and the stock backing plates has eliminated this movement. I suggest that you use the stock backing plates if you can.

2. Make sure you perform the proper bedding procedure to impregnate the rotor with pad material. This is critical if you want your new brakes to work well.

3. Opening the brake resevoir just allows you to move the pads away from the calipers by releasing some of the pressure in the system. Make sure you close this back up when finished.

The Carbotech pads I used were good, but ultimately they produced WAY too much noise to be useful as a replacement for stock pads and they were still not close to the level of pad I'd wanted for the track.

EDIT #1 (2010): My most recent track pad is the Hawk DTC 70 (w/ DTC 60 rear). These are true racing pads and are a world apart from stock when hot on the track. I am currently using a second set of stock front rotors, matched to the Hawk pads, as my track setup. Having separate rotors allows me to just swap and go, as opposed to having to bed the pads each time I swap street/track. EDIT: This year I added TiSpeed titanium backing plates to my setup to further insulate the brake fluid from the massive amount of heat our brakes generate. I can happily report that i had no brake fluid boiling issues in the 2010 season. Still wouldn't mind upgrading to an aftermarket big brake kit, but for now my setup is working well.

EDIT #2 (2012): Just to keep this up to date, I should admit that I finally replaced my stock calipers with Stoptech units and Endless pads. This mod was in conjunction with the move to Hoosier slick tires for the track and i can't begin to explain the difference on track with this setup. Ultimately I could not get comfortable with the performace level of the stock brakes and needed to make the change. If anyone is on the fence about this move please feel free to reach out because in retrospect is was absolutely worth it. By the way, with the Stoptechs I don't have to remove the calipers to change the pads!

I've switched my brake fluid to the Stoptech 660 racing fluid with which i had no issues all season.

The only things different for me was I was able to change both front pads with only taking out the T-40 holding bolts on one side of the front caliper and that gave enough room to angel and slide in the pad for the side with the bolts still on, then insert the other pad, hold in place, and reinstall the T-40s. And actually I was able to use the original backing plates on the front and one of the two on the back without issue. I did not experience or hear the pads shifting during bedding. I will look and see if they are up against the pins and report back.

The only things different for me was I was able to change both front pads with only taking out the T-40 holding bolts on one side of the front caliper and that gave enough room to angel and slide in the pad for the side with the bolts still on, then insert the other pad, hold in place, and reinstall the T-40s. And actually I was able to use the original backing plates on the front and one of the two on the back without issue. I did not experience or hear the pads shifting during bedding. I will look and see if they are up against the pins and report back.

Must admit that the pictures aren't mine. I stole them from Edmunds.com, but I did draw those awesome little arrows. I may look into putting the backing plates on the front pads since you say they fit on your car. I don't want to ruin the ceramic inserts by having the pad shift within the caliper.

My E30 repair manual recommends replacing the bolts that hold the caliper to the vehicle. I doubt if they put that in there (and those bolts are far heavier), it is any different with those allen bolts.

The only things different for me was I was able to change both front pads with only taking out the T-40 holding bolts on one side of the front caliper and that gave enough room to angel and slide in the pad for the side with the bolts still on, then insert the other pad, hold in place, and reinstall the T-40s. And actually I was able to use the original backing plates on the front and one of the two on the back without issue. I did not experience or hear the pads shifting during bedding. I will look and see if they are up against the pins and report back.

Can you explain again how you did this. I can't see how its possible to get the pads in through the holes in the top of the caliper...

The caliper has a anchor plate that bolts to the back of the "suspension knuckle" (BMW calls it the swivel bearing). According to the BMW TIS, you remove the caliper and the anchor plate as a unit. The torque for these two M12x1.5 bolts is 110 Nm and they are to be replaced with new ones upon reassembly. The two 10mm allen bolts have a locking agent on them and I imagine are designed to be permament (Real OEM shows the caliper and backing plate as a unit).

I looked all this up because I am going to change out my OEM struts for some Koni FSD struts and you drop the swivel bearing and strut as a unit to access the strut for replacement.

The caliper has a anchor plate that bolts to the back of the "suspension knuckle" (BMW calls it the swivel bearing). According to the BMW TIS, you remove the caliper and the anchor plate as a unit. The torque for these two M12x1.5 bolts is 110 Nm and they are to be replaced with new ones upon reassembly. The two 10mm allen bolts have a locking agent on them and I imagine are designed to be permament (Real OEM shows the caliper and backing plate as a unit).

I looked all this up because I am going to change out my OEM struts for some Koni FSD struts and you drop the swivel bearing and strut as a unit to access the strut for replacement.

Just installed a set of Cool Carbons on my 1351. Some of the tips here proved useful, however I do question the need to take off all 4 wheels at the same time. I started with the rears as the were going to be the easiest to do, and would reward with me some satisfaction in at least getting the job half done. The fronts I expected to be a challenge but things went very smoothly, and had no issue in removing the two bolts that hold the caliper on. Used a dab of Locktite on the T40 torx head bolts as wells as the two large bolts.

I suspect the reason BMW recommends new bolts each time is that their lawyers have warned them if these bolts are reused without thread locker, there is a remote possibility that they could back out if some shade tree mechanic or even a tech failed to torque the bolts to the proper spec. I would think it is not a case of the bolts being over stressed, the things are huge. (Please note this is only my opinion, not fact.)

Another nice thing about the Cool Carbons is they do have the cut outs from the brake sensors, and have backing plates installed; as well as detailed instructions on breaking in the brakes for the best results. Time will tell if they are fairly dustless, at any rate can't be nearly as horrible as the OEM pads.

I took all 4 wheels off because I was also changing the oil and bleeding the brakes. I figured it would be easiest to just have the car up on jack stands to get it all done. If I were to bleed the brakes at the track I would probably just do one at a time.

I didn't put any locktite on the allen bolts, but when I changed my wheels last weekend I checked the bolts and they were as tight as when I put them back in. I'm sure they'll be fine, and I'll just check them every so often.

The caliper has a anchor plate that bolts to the back of the "suspension knuckle" (BMW calls it the swivel bearing). According to the BMW TIS, you remove the caliper and the anchor plate as a unit. The torque for these two M12x1.5 bolts is 110 Nm and they are to be replaced with new ones upon reassembly. The two 10mm allen bolts have a locking agent on them and I imagine are designed to be permament (Real OEM shows the caliper and backing plate as a unit).

I looked all this up because I am going to change out my OEM struts for some Koni FSD struts and you drop the swivel bearing and strut as a unit to access the strut for replacement.

Thanks for the DIY post guys -- I just used this technique to replace my brakepads with Hawk Performance Ceramics. I plan to test them on the track with the AD08s this Friday. I know these are not track pads; but, this is not my track car and they have to be better then the stock pads plus I can already tell the dust is greatly reduced.

On the side of track pads. Because I ran out of time I replaced the front pads on the 911 with HT14s since the vendor was out of HT10s. I wish I had done that sooner. The balance with this setup is phenomenal. It was recommended on the Hawk site; but, now I wish I hadn't resisted it so long. Now it makes the way forward for track pads for this car less clear.

Why is it important to remove the 4 pins on the forward calipers? I changed my pads several times because the Hawk ceramic pads squealed big time everytime I came to a halt. I therefore had to go back to my old pads which I later returned the ceramics for HPS pads. So I had my pads in and out several times and never had to remove those pins. I just removed the caliper bolts and slid out the pads and put in the new ones. Has anyone else had the squealing problems with the Hawk ceramics? I was told that I had glazed them but they only squealed after driving 10-15 miles not initially. I embedded them as I should but I guess I didn't clean the old pad material off which was never posted anywhere. I'll have to see how these HPS pads will work out.

I just replaced my brake pads on all four corners with Cool Carbon. Here are some tips I learned in the process:

1) You don't have to open the brake cylinder cap for a even pad swap. If you are swapping out run out pads with new, then yes open and take out some fluid if necessary so you don't over flow when the pistons are pushed in.

2) You don't need to take out the 4 torx screws on the caliper. Like some one mentioned you can easily angle in the new pad on the spring clip and insert the pad into the recessed area of the caliper.

3) I believe it's certainly acceptable to remove the two hex caliper bolts for pad replacements. My Porsche uses the same basic caliper and the bolts are the same. I checked the Porsche Bentley manual and the torque specs are 85 n-m or 63 ft-lb. No problem here for caliper removal and it's the method for the Porsche when you need to replace the brake rotors.

4) A simple method for pushing the pistons in is to use channel lock plyers with some duct tape over the jaws so you don't scratch any paint. Squeeze the brake pad tabs with the four torx screws to pull in the pistons while the pads are still installed. I used this method all the time on Porsche Brembo calipers, but it was pad tabs to actual outside caliper. Works great. The rears can be done similarly with the big metal weights if necessary. But as indicated here you can use your fingers/hands.

I think that was it. A very simple process, but I prefer the Porsche brakes overall. They are simpler and very quick to swap out pads. You don't have to remove the front caliper on the Porsche either. Only one pin per caliper to remove.

Thanks for the great write-up. Question: My rear brake pad wear sensor broke when I tried to remove it from the pad. Now a yellow "BRAKE" idiot light comes on every time I start my 135. I taped up the cracked broken end with electrical tape and zip-tied the wire to secure it. I replaced my pads with CarboTech Bobcat (1521) aggressive street pads and as mentioned earlier they don't support the sensors. Do I have to replace the broken rear brake pad wear sensor to get the yellow "BRAKE" light in the instrument cluster to turn off even though I do not plan using it? Or is the only way to turn that message and yellow "BRAKE" light off is to go to the dealer to have them reset it?